It doesn’t get much bigger than Sunday’s game for the Portland Timbers. With a win over their biggest rival, Seattle Sounders FC, the team will take sole control of first place in Major League Soccer’s Western Conference.

The match is also Portland’s 100th in its MLS existence, and while it took the better part of three seasons to reach this point, head coach Caleb Porter’s revolution has turned it into a dangerous team. Many point to a league-high 14 draws in disdain, but the Timbers have failed to earn at least a point in just five of 18 games on the road in 2013. Only four of those ties have come at home.

That makes the Timbers a good bet for success in the playoffs, when games on the road become the bane of many good home teams. Just up the road in Seattle, the Sounders have made a habit of creating major deficits in the first leg away from home, losing 3-0 to Real Salt Lake in 2011 and the Los Angeles Galaxy in 2012.

Helped along by some stunning goalkeeping from Donovan Ricketts, Darlington Nagbe’s timely attacking prowess and Will Johnson’s leadership with the captain’s armband, the Timbers are in good shape heading into the last month of the season. Designated Player Diego Valeri has also proven his worth throughout the season.

After being tied for first place in June, injuries to key players took their toll for a while. Johnson, Valeri and Diego Chará all went down with various ailments. Now, with nearly everybody back to 100 percent, Portland can put that rough patch behind it.

Or at least, it looked that way, until Nagbe went down on Wednesday against the Vancouver Whitecaps.

Porter has been cagey about his star youngster’s injury, but it seems a little more serious than it initially looked. Nagbe, whose nine goals make him the single-season leading scorer for the Timbers, will be a vital part of any playoff run Portland makes.

The club can exorcise another demon on Sunday, when Seattle comes to town. This season, the teams have tied once, with the Sounders narrowly winning their second meeting. Not only can Porter get his first win over Seattle, but his team can ensure the Sounders won’t win the Cascadia Cup — not to mention taking first place.